Crankcase ventilating means for internal combustion engines



P 30,v 1959 R. L. WEBER ETAL 3,469,565

CRANKCASE VENTILATING MEANS FOR INTERNAL COMBUSTION ENGINES Filed Aug. 17, 1967 3 Sheets-Sheet l INVENTOR. ROBERT L WEBER 7 ATTORNEYS Sept. 30, 1969 R. L. WEBER ETAL CRANKCASE VENTILATING MEANS FOR INTERNAL COMBUSTION ENGINES Filed Aug. 17, 1967 3 Sheets-Sheet 2 IN LIN I I I I I I INVENTOR. ROBERT L. WEBER i w a; 72cm v I ATTORNEYS I P 30, v1969 I R. L. WEBER ETAL 3,469,565

CRANKCASE VENTILATING MEANS FOR INTERNAL COMBUSTION ENGINES Filed Aug. 17. 1967 N 3 sheets sheet 3 '-'v 3 m: 8 Zia O O 0 0 FT o o o o 0 La li 0 e o e o 9 B e a Q; ZIQ

INVENTORS ROBERT L. WEBER THOMAS M ALBRKSHT ATTORNEYS United States Patent 3,469,565 CRANKCASE VENTILATING MEANS FOR INTERNAL COMBUSTION ENGINES Robert L. Weber, Lacon, and Thomas M. Albright, Chillicothe, Ill., assignors to Caterpillar Tractor Co., Peoria,

Ill., a corporation of California Filed Aug. 17, 1967, Ser. No. 661,470 Int. Cl. F02m 25/06 US. Cl. 123-119 5 Claims ABSTRACT OF THE DISCLOSURE A ventilator valve is arranged to communicate blowby gases from the crankcase of an internal combustion engine to the intake manifold thereof for reburning purposes when such gases exceed a predetermined pressure level. The valve comprises a normally retracted valve means arranged to extend automatically when the pressure level is exceeded to effect such communication through the valve means. The valve means comprises a tubular sleeve slidably mounted on a tubular extension attached to a housing have a flexible diaphragm assembly mounted therein. The diaphragm assembly defines first and second chambers continuously communicating with atmospheric pressure and the crankcase, respectively, whereas the tubular extension defines a third chamber in continuous communication with the intake manifold.

Background of the invention Numerous methods and devices have been proposed for ventilating the crankcase of an internal combustion engine to the intake manifold thereof for the purpose of reburning blowby gases. The primary problem sought to be solved in one of preventing such gases from being admitted to the atmosphere directly via a breather pipe or the like. The blowby gases generally constitute unburned carbons which escape past the piston rings of the engine and into the crankcase thereof. One prior art solution to such problem is to provide a valve between the engines crankcase and intake manifold to vent the crankcase gases to the intake manifold whereafter they are mixed with the fuel-air mixture for combustion purposes. The valve should further function to prevent contaminants, such as dirt particles and water, from entering the intake manifold.

Summary of the invention The primary objects of this invention are to provide a non-complex, inexpensive, and efficient ventilating means for automatically venting gases from an engines crankcase to the intake manifold thereof. The ventilating means further functions to prevent contaminants, such as dirt particles and water, from entering the intake manifold during engine operation. In particular, such ventilating means comprises a normally retracted or compressed valve means arranged to extend to communicate the engines crankcase and intake manifold therethrough when the gas pressure in the crankcase exceeds a predetermined level.

The valve means may comprise a normally retracted coil spring or slotted tubular sleeve arranged between a flexible diaphragm and a conduit connected to the intake manifold. When the above mentioned pressure level is exceeded, the diaphragm will be moved to extend the valve means to communicate the crankcase and intake manifold through openings formed therethrough.

Brief description of the drawing FIG. 1 is a front elevational view of an internal combustion engine employing a first crankcase ventilatlng means embodiment of this invention therein;

3,469,565 Patented Sept. 30, 1969 Brief description of the preferred embodiments An internal combustion engine 10, illustrated in FIG. 1, comprises a crankcase 11 arranged in a conventional manner to have the enclosed chamber thereof communicate with a closed chamber formed by a rocker arm cover 12. An intake manifold 13 is suitably arranged on the engine to receive fresh air through a filter 14 for combustion purposes. During operation, the engines pistons (not shown) function in a conventional manner to permit a certain amount of so-called blowby gases to pass thereby. Such gases will collect in the chambers formed by crankcase 11 and rocker arm cover 12. This invention is drawn to a ventilating means 15 arranged to communicate the blowby gases from such chambers to the intake manifold automatically via a conduit 16.

Referring more particularly to FIG. 2, the first illustrated ventilating means embodiment comprises a twopart housing 17 having a circular diaphragm assembly 18 suitably arranged therein to form first and second chambers 19 and 20, respectively. One or more apertures 21 are preferably formed through a wall portion of housing 17 to communicate atmospheric pressure to chamber 19. The diaphragm assembly comprises superimposed cupshaped members 22 and 23 having centrally disposed portions of a flexible diaphragm 2'4 clamped therebetween by a threaded bolt 25.

The peripheral edge of flexible diaphragm 24 is secured between opposed flange portions of housing 17, as clearly illustrated in FIG. 2. It should be noted that the diaphragm assembly is normally maintained in this position so that outer edge portions of the diaphragm form a convolution arranged between the housing and the cup-shaped members. Such a convolution will permit limited flexing of the diaphragm assembly for purposes hereinafter explained.

The ventilating means further comprises a normally retracted or compressed valve means 26, preferably in the from of a coil spring, arranged to automatically extend or expand to communicate chamber 20 with intake manifold conduit 16. The spring is attached at one end of the diaphragm assembly by bolt 25 and at the other end thereof to the housing through an adapter 27. The adapter is arranged to afford an air-tight seal between conduit 16 and housing 17. The spring and attendant structures may be suitably constructed and arranged to normally maintain diaphragm assembly 18 in its FIG. 2 position wherein a third chamber formed in spring 26 is maintained in closed communication with the intake manifold.

During engine operation, the pressure of the crankcase gases and thus the pressure prevalent in chamber 20 will rise. When such pressure exceeds a predetermined level, the gas pressure in chamber 20 will act against the face of member 23 to move diaphragm assembly 18 rightwardly. Such movement is counteracted initially by the relatively low intake manifold pressure occurring in conduit 16, the resistance afforded by spring 26 and the atmospheric pressure prevalent in chamber 19.

Continued rightward movement of the diaphragm assembly will function to extend spring 26 to thus permit the crankcase gases to flow through the gradually enlarged openings formed between the springs coil and into intake manifold conduit 16. The relatively low pressure occurring in the intake manifold will create a pressure differential to aid in maintaining a high rate of gas flow through valve means 26. When the pressure in chamber 20 falls below the above-mentioned predetermined level, diaphragm assembly 18 will move leftwardly to retract spring 26 to its normally closed FIG. 2 position. Thus, communication between the crankcase and the intake manifold is prevented until such pressure level is again exceeded.

It should be understood that extensible valve means 26 could alternatively comprise an elastic (such as a stretchable plastic or rubber based constituent) bellows or other suitable tubular structure which will function similar to the above described spring. For example, normally closed slits could be formed through the side walls of a stretchable tube and arranged to open to communicate chamber 20 with the intake manifold when the tube is stretched.

FIGS. 3 and 4 illustrate a second ventilating means embodiment a, the corresponding components of the respective embodiments having identical numerals with the numerals of the second embodiment accompanied by a subscript a. A two part housing 17a has a circular diaphragm assembly 18a arranged therein to form first and second chambers 19a and 20a, respectively. Apertures 21a are preferably formed through a wall portion of the housing to communicate atmospheric pressure to chamber 19a. The diaphragm assembly comprises cupshaped members 22a and 23a having centrally disposed portions of a flexible diaphragm 24a clamped therebetween by a threaded bolt 25a in substantially the same manner as above described.

The ventilating means further comprises a normally retracted or compressed valve means 26a preferably in the form of a tapered plastic sleeve slidably mounted on a tubular portion 27a of housing 17a. The cup end of the tubular sleeve is attached to the diaphragm assembly by means of nut and bolt arrangement 25a. A spring means, preferably in the form of a coil spring 28, may be disposed in the manner illustrated to aid in urging the valve means to its normally closed position. However, in certain applications spring means 28 could be omitted and the valve means held in such closed position by the forces afforded by the atmospheric pressure prevalent in chamber 19a and/or the closing force afforded by the diaphragm assembly.

As more clearly illustrated in FIG. 4, sleeve 26a has a plurality of apertures 29, preferably slots, arranged therethrough to progressively increase the communication between chamber 20a and intake manifold 13 (FIG. 1) when valve means 26a is extended or expanded. A perforated cylinder 30 may be arranged in chamber 20a (and also chamber 20 of the first described embodiment) to surround the valve means. The cylinder will thus function as an oil separator to prevent appreciable amounts of oil from being discharged into the intake manifold along with the crankcase fumes.

Thus it can be seen that valve means 26a will extend relative to tubular portion 2711 when the gas pressure in chamber 20a exceeds a predetermined level in much the same manner as described in connection with the operation of the FIG. 2 embodiment. The FIGS. 3 and 4 embodiment may be, of course, operatively connected to an internal combustion engine in the manner illustrated in FIG. 1.

It should be understood that the second described embodiment could be modified slightly without departing from the scope of this invention. For example, sleeve or valve means 26a could be mounted interiorly of tubular portion 27a with slots corresponding to slots 29 formed in the sleeve and/or such tubular portion. Also, slots 29 could comprise a plurality of suitably arranged circular holes.

We claim:

1. In an internal combustion engine comprising an intake manifold, a crankcase and ventilating means for automatically venting gases from said crankcase to said intake manifold when the pressure of said gases exceeds a predetermined level, said ventilating means comprising a normally retracted and extensible valve means having a plurality of normally closed apertures formed therein and arranged to extend to gradually and progressively open said apertures to communicate said crankcase and intake manifold therethrough when the pressure of said gases exceeds said predetermined level, a housing having a flexible diaphragm assembly arranged therein to form first and second chambers, said first and second chambers communicating with atmospheric pressure and said crankcase, respectively, said valve means comprising a tubular sleeve slidably mounted on and axially aligned with a tubular extension attached to said housing, said tubular extension defining a third chamber therein continuously communicating with said intake manifold, said tubular sleeve comprising a cup end portion attached to said diaphragm assembly and normally abutting an open end of said tubular extension and said third chamber to normally prevent said second chamber from communicating with said third chamber when said valve means is retracted and for permitting such communication through said apertures when said valve means is extended.

2. The invention of claim 1 wherein said diaphragm assembly comprises superimposed cup-shaped members having centrally disposed portions of a flexible diaphragm clamped therebetween, peripheral edges of said flexible diaphragm secured to said housing and arranged to form a convolution in said flexible diaphragm between said cup-shaped members and said housing.

3. The invention of claim 1 wherein said tubular sleeve has said plurality of apertures formed therethrough and arranged to progressively increase communication between said crankcase and intake manifold when said valve means is extended.

4. The invention of claim 1 further comprising spring means arranged to maintain said valve means in its normally retracted condition.

5. The invention of claim 1 further comprising a perforated cylinder arranged to surround said valve means for preventing oil from being discharged into said intake manifold.

References Cited UNITED STATES PATENTS 1,395,932 11/1921 Staude. 2,125,435 8/ 1938 Erling. 3,056,420 10/ 1962 Dietrich. 3,159,150 12/ 1964 Humphreys. 3,170,448 2/ 1965 Campbell. 3,262,436 7/ 1966 Thompson. 3,312,207 4/1967 Martin et a1. 2,775,960 1/ 1957 Druzynski. 3,108,581 10/ 1963 Humphreys. 3,144,011 8/1964 Anthes. 3,241,537 3/1966 Jones.

FOREIGN PATENTS 526,151 9/ l940 Great Britain.

AL LAWRENCE SMITH, Primary Examiner U.S. C1. X.R. 137--479 

